A U.S. appeals court on Thursday overturned a 2012 verdict against Kolon Industries Inc. of South Korea that awarded DuPont Co. $919.9 million in damages.

DuPont, the largest U.S. chemical firm by market value, has alleged its South Korean rival stole some trade secrets for Kevlar, a fiber used to make tires, fiber-optic cables and bullet-proof vests.

In 2012, jurors in a federal court in Richmond, Va., delivered a verdict in favor of DuPont, ordering Kolon to pay $919.9 million.

But the 4th U.S. Circuit Court of Appeals in the city threw out the verdict, saying the judge wrongly excluded evidence related to Kolon's defense. It ordered a new trial under a different trial judge.

DuPont said it is disappointed by the appeals court decision.

 "We will continue to vigorously pursue Kolon to hold them accountable and are confident that we will prevail," Thomas Sager, DuPont's general counsel, said in a statement.

Kolon, meanwhile, has denied the patent theft charges, saying DuPont has made public details about Kevlar for a long time. (Yonhap)